IS 4432:1988 15Cr3 Steel: Specifications & Listings
IS 4432:1988 15Cr3: 15Cr3 is a case hardening steel in IS 4432:1988 (Specification for case hardening steels), which covers wrought low carbon unalloyed and alloy steel bars, billets, rods and finished forgings for case hardening.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Si
Mn
Cr
S
P
0.12-0.18
0.15-0.35
0.40-0.60
0.50-0.80
<=0.035
<=0.035
Mechanical Properties
Core Tensile Strength
650-900 MPa (16 mm) / 600-900 MPa (30 mm)
Core Yield Strength
>=430 MPa (16 mm) / >=360 MPa (30 mm)
Core Elongation
>=12% (16 mm) / >=14% (30 mm)
Core Reduction of Area
>=35% (16 mm) / >=40% (30 mm)
Hardness, annealed (A)
<=174 HB
More data from IS 4432:1988
From the standard
Sulphur and phosphorus limitsordering options
Sulphur and phosphorus
0.035 percent max each
Narrower sulphur range
Order as 15Cr3-S: sulphur 0.020 to 0.035, phosphorus 0.035 max
Sulphur and phosphorus range can also be ordered under clause 5.1, Limit 2.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 1 note 1, clause 5.1, Table 2 note 1
Other composition limitsfrom the clauses and notes
Deoxidation
Fully killed, unless otherwise agreed
Elements not specified for this grade, if present, maximum
Ni 0.30, Cu 0.25, V 0.05, Mo 0.05 percent
Copper plus 10 times tin, maximum
0.50 percent
Micro-alloying elements
Titanium, niobium, vanadium or boron may be added by agreement, singly or together
Elements not specified in Table 1 are not added except by agreement or to finish the heat. Reasonable precautions are taken against unwanted elements from scrap.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 1 notes, clauses 3, 3.1 and 5.3
Heat treatment temperatures4 values
Hot working temperature range
1100 to 850 °C
Normalising temperature
880 to 910 °C
Full annealing (A) temperature
880 to 910 °C
Sub-critical anneal for softening, after normalising
650 to 700 °C
Recommended temperatures, for guidance only, for controlling hardness, machinability and shearability.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 3
Case hardening treatment6 values
Carburising temperature
890 to 940 °C
Direct and single hardening temperature
820 to 850 °C
Double hardening, core hardening temperature
870 to 890 °C
Double hardening, case hardening temperature
780 to 820 °C
Quenching medium
Oil / water
Tempering temperature
170 to 200 °C
Recommended conditions for reaching the core properties below, for guidance only. Time for austenitising about 45 minutes for a 25 mm section; tempering at least 1 hour, preferably 90 minutes. For direct and single quenching use fully aluminium killed fine grained steel. If direct hardened, a carburising temperature of 940 °C is generally not exceeded. Thermal bath includes suitable salt baths.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 5
Core properties after case hardening, by test bar diameter2 sections
Tensile strength (MPa)
Yield strength, min (MPa)
Elongation, min (%)
Reduction of area, min (%)
Test bar diameter (mm)
650 to 900
430
12
35
16
600 to 900
360
14
40
30
Core properties of simulated case-hardened test bars, treated as in the case hardening treatment above. Values apply to test bars taken from rounds in the direction of rolling. Applies when the steel is ordered on this basis.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 4
Hardness by delivery condition3 conditions
As rolled (R), maximum
202 HB
Annealed to maximum hardness (A), maximum
174 HB
Treated for improved machinability (M)
120 to 180 HB
Brinell hardness. A different as-rolled maximum for cold shearability, or a different range for improved machinability, may be agreed at the time of order.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 6, clause 7.2
Hardenability, end quench testHardness band
Distance from quenched end (mm)
1.5
5
20
30
40
Maximum, HRC
47
44
31
28
-
Minimum, HRC
-
-
-
-
-
Recommended values. Jominy test as per IS 3848. Minor variation in ladle analysis from Table 1 is permitted for steel with guaranteed hardenability.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 7
Blank hardened hardnesscore strength guarantee
Blank hardened hardness, HRC
28
Blank hardening treatment
880 ± 10 °C, followed by water quenching
Blank hardening is done on a 30 mm diameter turned specimen from the same location of the billet as the tensile specimen; hardness is taken at the centre. Recommended value, applies when agreed.
Source: IS 4432:1988 with Amendment 1 (April 1994), Table 7 notes 1 and 2, clause 14.1 (d)
Active IS 4432:1988 15Cr3 Listings on M-EX (For Sale)